300 Ultra Mag Barrel Life?

[mountaincarver]

The last couple of times ive been out with my ultra, ive noticed a drop in accuracy. my best load was shooting 3/4 moa at 200 yards consistantly. ive been a little worried about the gun lately, so i went out and tested my best load. i found that it is shooting slightly over moa at 200 yards (about 2.5 inches). Ive probably got about 500 rounds through the gun. Checking the gun over, i dont believe i have a problem with scope or stock. Ive read mixed opinions on number of rounds for a drop in accuracy with an ultra mag. does anyone have experience with this? i can tell you that i cant see anything obviouse with a not so good quality bore scope.

 

[Jokostel]

800-1200 Rounds is not out of the question.
However, at 500 rounds, I'm sure you have some evident throat erosion.
I would go thru the weapon with a fine tooth comb if you haven't already... and scrub the bore out with something like 7.62 sweets that removes copper AND general powder fouling...
I also LOVE Kroil and CLP. Kroil is a type of cleaner and oil that's very light and digs into the molecular level of the steel. I always SOAK the barrel in that when done cleaning.... and when I bring a new rifle home.
CLP is also a great "finishing" lube and cleaner.

If a good cleaning doesn't help, at that round count, your load may have fallen out of favor, and you'll probably have to seat the bullet out another 5-10 thou.
Worst comes to worst, take it to a gunsmith with a bore light and have them inspect it.

 

[BountyHunter]

look for a carbon ring at the throat/chamber junction also.

 

[johnnyk]

look for a carbon ring at the throat/chamber junction also.

+1. Had one develop in my 6.5-284 Norma at the end of last summer. Guys on here suggested GM Top Engine cleaner, and if I couldn't get that try Sea Foam. Got the Sea Foam and cleaned it thoroughly. After two days of cleaning, I took it back out and walah! back in the saddle. I use it in every cleaning now. Hoppes first, Sea Foam and then an ammonia based copper remover.

Think my .300WinMag is developing one. Will start cleaning it out tomorrow. Good luck with your RUM. Let us know how it goes. JohnnyK.

 

[TXAoudadKlr]

Id imagine there's some throat erosion by the 500 round mark. Perhaps tweaking the load and a good barrel cleaning session may do the trick.

 

[Frank in the Laurels]

As long as you don't go crazy every year, a lifetime....fire form your brass...pick a great hunting bullet...load up a doo a little testing..sight in...put away until each hunting season...pick a much easy cartridge to play with, cheaper, less recoil and readily available components... One word of advice..I use Kroil also but do not get it in your trigger, it will gum up so bad you can't fire the gun!!! Run lighter fluid down through it if you think so kroil got in there.

 

[Jokostel]

As long as you don't go crazy every year, a lifetime....fire form your brass...pick a great hunting bullet...load up a doo a little testing..sight in...put away until each hunting season...pick a much easy cartridge to play with, cheaper, less recoil and readily available components... One word of advice..I use Kroil also but do not get it in your trigger, it will gum up so bad you can't fire the gun!!! Run lighter fluid down through it if you think so kroil got in there.

Did you read the post at ALL?
Said hes got 500+ rounds on the pipe.

 

[jjmp]

All good answers but Frank's got a good one to ! It does burn a significant amount of powder just saying

 

[mountaincarver]

Thank you for the replies. OK, I took the gun out and basically went through some load testing. the gun shot as good as it ever has (1.25 inch 200 yards) after reducing the powder charge by quite a bit. I never moved the bullet. basically what I ended up with is a node (with 230 bergers) at 2908 fps instead of 3000 fps with 5 more grains of powder (H50). cant seem to get the gun to shoot accurately at the fast speed it used to but...... anyway, I don't know what exactly the correct terms to use for this situation, but something has definitely changed whether it be called wearing out or breaking in. I'm glad it worked out this way instead of a worthless gun sitting around.

 

[TackDriv3r]

Thank you for the replies. OK, I took the gun out and basically went through some load testing. the gun shot as good as it ever has (1.25 inch 200 yards) after reducing the powder charge by quite a bit. I never moved the bullet. basically what I ended up with is a node (with 230 bergers) at 2908 fps instead of 3000 fps with 5 more grains of powder (H50). cant seem to get the gun to shoot accurately at the fast speed it used to but...... anyway, I don't know what exactly the correct terms to use for this situation, but something has definitely changed whether it be called wearing out or breaking in. I'm glad it worked out this way instead of a worthless gun sitting around.

Have you tried the slow burning Reloader powders?

 

[Wedgy]

One of my RUMs did the same thing but I found a good size carbon ring had not been removed from the standard cleaning. JB bore paste and their brush works pretty well, I will also spin it slowly on a cordless drill. I only clean the ring with the abrasive as the rest will come out with solvents. I used Cameleon before but it was indicating clean but the borescope showed there was still carbon there.

 

[Rifleman513]

My RUM has about 400 rounds through it and it is shooting as good as it ever has. Two things that I have done since I've had it, I'm a stickler for cleaning it and never let it get hot while shooting.

I second the kroil and copper solvent. I also always use nylon brushes when possible. I am probably over doing it but when I take it out I set a timer on my phone and wait 4 min between each shot.

May not help much but so far it has worked well enough for me.

 

[TXAoudadKlr]

I'm curious as to how can you prevent a carbon ring from forming.

 

[Jokostel]

Proper cleaning.... until the barrel starts wearing, then a gunsmith with a borescope is needed.